How effective is Ship armour in Star Wars?

[Straha]

This is a question directly spawned from the exposed bridges thread. One of the explanations given for the nature of the bridges is "With Gigaton blasts being thrown around by the ships in question it really doesn't matter where you place the bridge once the shields go down." So my question is this: How effective are battleship hulls in Star Wars when compared with the offensive weaponry in universe? Are they really nothing more than a shell around shield generators or could ships stand up to turbolaser fire without their shields for an extended length of time?

[Fingolfin_Noldor]

Well, Invisible Hand was having chunks of her armour ripped out under the fire of the Gualaura.

What is apparent, is that the ships have varying armour thickness. The weaker areas, which are obvious enough, get penetrated more easily compared to the meatier chunks. In the broadsides between Gualaura and Invisible Hand, the weaker sections tend to be targeted by the shorter range weapons while the heavy turbolaser turrets of the Gualaura were targeting the thicker sections. It was the same for the Invisible Hand as well.

In another instance, there was this ISD in ROTJ that took a shot right on the top of the reactor and subsequently blew up. The frontal area of the ISD (the area with all the windows) seem to be the areas with weaker armour.

[FA Xerrik]

Additionally, in ANH, there are several shots of starfighters directly strafing the Death Star's armor. It's difficult to say whether a deflection tower would have less armor for some reason due to it's function in maintaining shields, or indeed would have more for the same reason. There is also a shot of Luke targeting armor plate, causing a lot of pyrotechnics to be thrown around and at least some structural damage, evidenced by the crew and troopers in adjacent sections being knocked around somewhat in the next scene. Granted these scenes don't provide a lot to go on as far as extent of the damage, beyond destruction of the deflection tower. They do, however, put some sort of lower limit on station-grade armor, as starfighter lasers seem to be at least marginally effective.

[Silver Jedi]

This quote is regarding a black mark on the hill of an Acclamator:

"Enemy fusion rockets barely score the super-dispersive neutronium-impregnated hull cladding"

"Fusion rockets" implies to me nuclear weapons, however, that can just as easily mean fighter grade weapons.

[Connor MacLeod]

the ICSes also mention the use of "powered" dispersive armour. Its quite liekly that there's more to it than sheer theraml resilience or density. We know the DS's surface had some independent ray/particle shielding over at least some sections, and other vessels (like Slave-1) supposedly had hull-based ray shielding.

IIRC Mike also once suggested that the shield generator heat sinks might be positioned to double as armor, or that the armor itself may have heat sink like properties (or be connected to them in some way as a redundancy measure.)

We also know from various soures (EGW&T and DK books) that the ship's armour and structure can have "hull enahnced" via tensor fields or secondary particle shield functions -= indeed some sourceces indicat shields and armour do interact in some manner, which may enhance/complement defensive properties (and with the "segmented" nature of shields, IE hoth shield in TESB, losing one section won't neccesarily compromise armour integrity.